1. Field of the Invention
The present invention relates to a controller for controlling an automatic assembling apparatus such as an automatic assembling robot and, more particularly, to an improvement, i.e., a simple arrangement of an automatic assembling apparatus.
2. Prior Art
Conventional automatic assembling apparatuses are largely classified into a so-called "line system" and a "non-line system".
In the "line system", a plurality of automatic assembling apparatuses aligned in an assembling order sequentially assemble a final product from one part. In the "line system" automatic assembling apparatus, an assembling robot has a single function, and supply of parts necessary for assembly is also simple. Therefore, the assembling apparatus and a controller therefor have a one-to-one correspondence. In other words, one assembling apparatus requires one controller.
On the other hand, in the "non-line system", one automatic assembling apparatus assembles a final product from a plurality of parts. For example, U.S. patent application Ser. Nos. 903,412 and 887,130 mentioned above and "Article Feeding Apparatus" filed to the U.S. Patent Office on the same date as the present application are known. In these non-line system automatic assembling apparatuses, functions such as feeding of parts to an assembling robot, supply of parts to a supply means of the parts, and replenishment from external equipment (e.g., warehouse) to the supply means are important.
In the "non-line system" automatic assembling apparatus, if the number of parts to be assembled is increased, assembling processes are complicated, and parts supply to the robot is also complicated. As a result, not only in assembly but also in parts supply to the robot, precise control, especially, control synchronous with an assembling operation of the robot, is necessary.
In this case, a plurality of so-called robot controllers are merely connected to eliminate the conventional drawbacks. In the conventional controller, since the number of shafts and the number of inputs/outputs that can be controlled by one controller are limited, if the number of shafts and the number of input/output points exceed this limitations, a plurality of controllers must be arranged. However, even though the control size is enlarged, an increase in number of controllers results in disadvantages in terms of cost, power consumption, occupying area, and the like.
An increase in number of controllers also causes the following disadvantages. That is, the assembly, feeding, supply, and replenishment functions must be independently operated in view of efficient assembly. For this purpose, teaching must be performed in units of functions. Since teaching requires an operation unit and a display unit, if a controller is provided for each function, the operation unit and the display unit must be provided to each function unit. A plurality of sets of operation units and display units will not be basically operated at the same time. Therefore, it is inefficient to arrange a plurality of operation units and display units. An increase in number of controllers also results in the following drawback. That is, in an NC machine such as a robot assembling apparatus, a teaching pendant (=input console of teaching data) is used for teaching. If a plurality of controllers are arranged, teaching must be performed for each controller, and data must be input using the teaching pendant while moving to each controller, making operation cumbersome.